PostgreSQL Source Code  git master
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros
localtime.c
Go to the documentation of this file.
1 /*
2  * This file is in the public domain, so clarified as of
3  * 1996-06-05 by Arthur David Olson.
4  *
5  * IDENTIFICATION
6  * src/timezone/localtime.c
7  */
8 
9 /*
10  * Leap second handling from Bradley White.
11  * POSIX-style TZ environment variable handling from Guy Harris.
12  */
13 
14 /* this file needs to build in both frontend and backend contexts */
15 #include "c.h"
16 
17 #include <fcntl.h>
18 
19 #include "datatype/timestamp.h"
20 #include "private.h"
21 #include "pgtz.h"
22 #include "tzfile.h"
23 
24 
25 #ifndef WILDABBR
26 /*
27  * Someone might make incorrect use of a time zone abbreviation:
28  * 1. They might reference tzname[0] before calling tzset (explicitly
29  * or implicitly).
30  * 2. They might reference tzname[1] before calling tzset (explicitly
31  * or implicitly).
32  * 3. They might reference tzname[1] after setting to a time zone
33  * in which Daylight Saving Time is never observed.
34  * 4. They might reference tzname[0] after setting to a time zone
35  * in which Standard Time is never observed.
36  * 5. They might reference tm.TM_ZONE after calling offtime.
37  * What's best to do in the above cases is open to debate;
38  * for now, we just set things up so that in any of the five cases
39  * WILDABBR is used. Another possibility: initialize tzname[0] to the
40  * string "tzname[0] used before set", and similarly for the other cases.
41  * And another: initialize tzname[0] to "ERA", with an explanation in the
42  * manual page of what this "time zone abbreviation" means (doing this so
43  * that tzname[0] has the "normal" length of three characters).
44  */
45 #define WILDABBR " "
46 #endif /* !defined WILDABBR */
47 
48 static const char wildabbr[] = WILDABBR;
49 
50 static const char gmt[] = "GMT";
51 
52 /* The minimum and maximum finite time values. This assumes no padding. */
55 
56 /*
57  * The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
58  * We default to US rules as of 1999-08-17.
59  * POSIX 1003.1 section 8.1.1 says that the default DST rules are
60  * implementation dependent; for historical reasons, US rules are a
61  * common default.
62  */
63 #define TZDEFRULESTRING ",M4.1.0,M10.5.0"
64 
65 /* structs ttinfo, lsinfo, state have been moved to pgtz.h */
66 
67 enum r_type
68 {
69  JULIAN_DAY, /* Jn = Julian day */
70  DAY_OF_YEAR, /* n = day of year */
71  MONTH_NTH_DAY_OF_WEEK /* Mm.n.d = month, week, day of week */
72 };
73 
74 struct rule
75 {
76  enum r_type r_type; /* type of rule */
77  int r_day; /* day number of rule */
78  int r_week; /* week number of rule */
79  int r_mon; /* month number of rule */
80  int32 r_time; /* transition time of rule */
81 };
82 
83 /*
84  * Prototypes for static functions.
85  */
86 
87 static struct pg_tm *gmtsub(pg_time_t const *, int32, struct pg_tm *);
88 static bool increment_overflow(int *, int);
90 static struct pg_tm *timesub(pg_time_t const *, int32, struct state const *,
91  struct pg_tm *);
92 static bool typesequiv(struct state const *, int, int);
93 
94 
95 /*
96  * Section 4.12.3 of X3.159-1989 requires that
97  * Except for the strftime function, these functions [asctime,
98  * ctime, gmtime, localtime] return values in one of two static
99  * objects: a broken-down time structure and an array of char.
100  * Thanks to Paul Eggert for noting this.
101  */
102 
103 static struct pg_tm tm;
104 
105 /* Initialize *S to a value based on GMTOFF, ISDST, and ABBRIND. */
106 static void
107 init_ttinfo(struct ttinfo * s, int32 gmtoff, bool isdst, int abbrind)
108 {
109  s->tt_gmtoff = gmtoff;
110  s->tt_isdst = isdst;
111  s->tt_abbrind = abbrind;
112  s->tt_ttisstd = false;
113  s->tt_ttisgmt = false;
114 }
115 
116 static int32
117 detzcode(const char *codep)
118 {
119  int32 result;
120  int i;
121  int32 one = 1;
122  int32 halfmaxval = one << (32 - 2);
123  int32 maxval = halfmaxval - 1 + halfmaxval;
124  int32 minval = -1 - maxval;
125 
126  result = codep[0] & 0x7f;
127  for (i = 1; i < 4; ++i)
128  result = (result << 8) | (codep[i] & 0xff);
129 
130  if (codep[0] & 0x80)
131  {
132  /*
133  * Do two's-complement negation even on non-two's-complement machines.
134  * If the result would be minval - 1, return minval.
135  */
136  result -= !TWOS_COMPLEMENT(int32) &&result != 0;
137  result += minval;
138  }
139  return result;
140 }
141 
142 static int64
143 detzcode64(const char *codep)
144 {
145  uint64 result;
146  int i;
147  int64 one = 1;
148  int64 halfmaxval = one << (64 - 2);
149  int64 maxval = halfmaxval - 1 + halfmaxval;
150  int64 minval = -TWOS_COMPLEMENT(int64) -maxval;
151 
152  result = codep[0] & 0x7f;
153  for (i = 1; i < 8; ++i)
154  result = (result << 8) | (codep[i] & 0xff);
155 
156  if (codep[0] & 0x80)
157  {
158  /*
159  * Do two's-complement negation even on non-two's-complement machines.
160  * If the result would be minval - 1, return minval.
161  */
162  result -= !TWOS_COMPLEMENT(int64) &&result != 0;
163  result += minval;
164  }
165  return result;
166 }
167 
168 static bool
170 {
172  return 0;
173  return t1 - t0 == SECSPERREPEAT;
174 }
175 
176 /* Input buffer for data read from a compiled tz file. */
178 {
179  /* The first part of the buffer, interpreted as a header. */
180  struct tzhead tzhead;
181 
182  /* The entire buffer. */
183  char buf[2 * sizeof(struct tzhead) + 2 * sizeof(struct state)
184  + 4 * TZ_MAX_TIMES];
185 };
186 
187 /* Local storage needed for 'tzloadbody'. */
189 {
190  /* We don't need the "fullname" member */
191 
192  /* The results of analyzing the file's contents after it is opened. */
193  struct
194  {
195  /* The input buffer. */
197 
198  /* A temporary state used for parsing a TZ string in the file. */
199  struct state st;
200  } u;
201 };
202 
203 /* Load tz data from the file named NAME into *SP. Read extended
204  * format if DOEXTEND. Use *LSP for temporary storage. Return 0 on
205  * success, an errno value on failure.
206  * PG: If "canonname" is not NULL, then on success the canonical spelling of
207  * given name is stored there (the buffer must be > TZ_STRLEN_MAX bytes!).
208  */
209 static int
210 tzloadbody(char const * name, char *canonname, struct state * sp, bool doextend,
211  union local_storage * lsp)
212 {
213  int i;
214  int fid;
215  int stored;
216  ssize_t nread;
217  union input_buffer *up = &lsp->u.u;
218  int tzheadsize = sizeof(struct tzhead);
219 
220  sp->goback = sp->goahead = false;
221 
222  if (!name)
223  {
224  name = TZDEFAULT;
225  if (!name)
226  return EINVAL;
227  }
228 
229  if (name[0] == ':')
230  ++name;
231 
232  fid = pg_open_tzfile(name, canonname);
233  if (fid < 0)
234  return ENOENT; /* pg_open_tzfile may not set errno */
235 
236  nread = read(fid, up->buf, sizeof up->buf);
237  if (nread < tzheadsize)
238  {
239  int err = nread < 0 ? errno : EINVAL;
240 
241  close(fid);
242  return err;
243  }
244  if (close(fid) < 0)
245  return errno;
246  for (stored = 4; stored <= 8; stored *= 2)
247  {
248  int32 ttisstdcnt = detzcode(up->tzhead.tzh_ttisstdcnt);
249  int32 ttisgmtcnt = detzcode(up->tzhead.tzh_ttisgmtcnt);
254  char const *p = up->buf + tzheadsize;
255 
256  if (!(0 <= leapcnt && leapcnt < TZ_MAX_LEAPS
257  && 0 < typecnt && typecnt < TZ_MAX_TYPES
258  && 0 <= timecnt && timecnt < TZ_MAX_TIMES
259  && 0 <= charcnt && charcnt < TZ_MAX_CHARS
260  && (ttisstdcnt == typecnt || ttisstdcnt == 0)
261  && (ttisgmtcnt == typecnt || ttisgmtcnt == 0)))
262  return EINVAL;
263  if (nread
264  < (tzheadsize /* struct tzhead */
265  + timecnt * stored /* ats */
266  + timecnt /* types */
267  + typecnt * 6 /* ttinfos */
268  + charcnt /* chars */
269  + leapcnt * (stored + 4) /* lsinfos */
270  + ttisstdcnt /* ttisstds */
271  + ttisgmtcnt)) /* ttisgmts */
272  return EINVAL;
273  sp->leapcnt = leapcnt;
274  sp->timecnt = timecnt;
275  sp->typecnt = typecnt;
276  sp->charcnt = charcnt;
277 
278  /*
279  * Read transitions, discarding those out of pg_time_t range. But
280  * pretend the last transition before time_t_min occurred at
281  * time_t_min.
282  */
283  timecnt = 0;
284  for (i = 0; i < sp->timecnt; ++i)
285  {
286  int64 at
287  = stored == 4 ? detzcode(p) : detzcode64(p);
288 
289  sp->types[i] = at <= time_t_max;
290  if (sp->types[i])
291  {
292  pg_time_t attime
293  = ((TYPE_SIGNED(pg_time_t) ? at < time_t_min : at < 0)
294  ? time_t_min : at);
295 
296  if (timecnt && attime <= sp->ats[timecnt - 1])
297  {
298  if (attime < sp->ats[timecnt - 1])
299  return EINVAL;
300  sp->types[i - 1] = 0;
301  timecnt--;
302  }
303  sp->ats[timecnt++] = attime;
304  }
305  p += stored;
306  }
307 
308  timecnt = 0;
309  for (i = 0; i < sp->timecnt; ++i)
310  {
311  unsigned char typ = *p++;
312 
313  if (sp->typecnt <= typ)
314  return EINVAL;
315  if (sp->types[i])
316  sp->types[timecnt++] = typ;
317  }
318  sp->timecnt = timecnt;
319  for (i = 0; i < sp->typecnt; ++i)
320  {
321  struct ttinfo *ttisp;
322  unsigned char isdst,
323  abbrind;
324 
325  ttisp = &sp->ttis[i];
326  ttisp->tt_gmtoff = detzcode(p);
327  p += 4;
328  isdst = *p++;
329  if (!(isdst < 2))
330  return EINVAL;
331  ttisp->tt_isdst = isdst;
332  abbrind = *p++;
333  if (!(abbrind < sp->charcnt))
334  return EINVAL;
335  ttisp->tt_abbrind = abbrind;
336  }
337  for (i = 0; i < sp->charcnt; ++i)
338  sp->chars[i] = *p++;
339  sp->chars[i] = '\0'; /* ensure '\0' at end */
340 
341  /* Read leap seconds, discarding those out of pg_time_t range. */
342  leapcnt = 0;
343  for (i = 0; i < sp->leapcnt; ++i)
344  {
345  int64 tr = stored == 4 ? detzcode(p) : detzcode64(p);
346  int32 corr = detzcode(p + stored);
347 
348  p += stored + 4;
349  if (tr <= time_t_max)
350  {
352  = ((TYPE_SIGNED(pg_time_t) ? tr < time_t_min : tr < 0)
353  ? time_t_min : tr);
354 
355  if (leapcnt && trans <= sp->lsis[leapcnt - 1].ls_trans)
356  {
357  if (trans < sp->lsis[leapcnt - 1].ls_trans)
358  return EINVAL;
359  leapcnt--;
360  }
361  sp->lsis[leapcnt].ls_trans = trans;
362  sp->lsis[leapcnt].ls_corr = corr;
363  leapcnt++;
364  }
365  }
366  sp->leapcnt = leapcnt;
367 
368  for (i = 0; i < sp->typecnt; ++i)
369  {
370  struct ttinfo *ttisp;
371 
372  ttisp = &sp->ttis[i];
373  if (ttisstdcnt == 0)
374  ttisp->tt_ttisstd = false;
375  else
376  {
377  if (*p != true && *p != false)
378  return EINVAL;
379  ttisp->tt_ttisstd = *p++;
380  }
381  }
382  for (i = 0; i < sp->typecnt; ++i)
383  {
384  struct ttinfo *ttisp;
385 
386  ttisp = &sp->ttis[i];
387  if (ttisgmtcnt == 0)
388  ttisp->tt_ttisgmt = false;
389  else
390  {
391  if (*p != true && *p != false)
392  return EINVAL;
393  ttisp->tt_ttisgmt = *p++;
394  }
395  }
396 
397  /*
398  * If this is an old file, we're done.
399  */
400  if (up->tzhead.tzh_version[0] == '\0')
401  break;
402  nread -= p - up->buf;
403  memmove(up->buf, p, nread);
404  }
405  if (doextend && nread > 2 &&
406  up->buf[0] == '\n' && up->buf[nread - 1] == '\n' &&
407  sp->typecnt + 2 <= TZ_MAX_TYPES)
408  {
409  struct state *ts = &lsp->u.st;
410 
411  up->buf[nread - 1] = '\0';
412  if (tzparse(&up->buf[1], ts, false)
413  && ts->typecnt == 2)
414  {
415  /*
416  * Attempt to reuse existing abbreviations. Without this,
417  * America/Anchorage would stop working after 2037 when
418  * TZ_MAX_CHARS is 50, as sp->charcnt equals 42 (for LMT CAT CAWT
419  * CAPT AHST AHDT YST AKDT AKST) and ts->charcnt equals 10 (for
420  * AKST AKDT). Reusing means sp->charcnt can stay 42 in this
421  * example.
422  */
423  int gotabbr = 0;
424  int charcnt = sp->charcnt;
425 
426  for (i = 0; i < 2; i++)
427  {
428  char *tsabbr = ts->chars + ts->ttis[i].tt_abbrind;
429  int j;
430 
431  for (j = 0; j < charcnt; j++)
432  if (strcmp(sp->chars + j, tsabbr) == 0)
433  {
434  ts->ttis[i].tt_abbrind = j;
435  gotabbr++;
436  break;
437  }
438  if (!(j < charcnt))
439  {
440  int tsabbrlen = strlen(tsabbr);
441 
442  if (j + tsabbrlen < TZ_MAX_CHARS)
443  {
444  strcpy(sp->chars + j, tsabbr);
445  charcnt = j + tsabbrlen + 1;
446  ts->ttis[i].tt_abbrind = j;
447  gotabbr++;
448  }
449  }
450  }
451  if (gotabbr == 2)
452  {
453  sp->charcnt = charcnt;
454  for (i = 0; i < ts->timecnt; i++)
455  if (sp->ats[sp->timecnt - 1] < ts->ats[i])
456  break;
457  while (i < ts->timecnt
458  && sp->timecnt < TZ_MAX_TIMES)
459  {
460  sp->ats[sp->timecnt] = ts->ats[i];
461  sp->types[sp->timecnt] = (sp->typecnt
462  + ts->types[i]);
463  sp->timecnt++;
464  i++;
465  }
466  sp->ttis[sp->typecnt++] = ts->ttis[0];
467  sp->ttis[sp->typecnt++] = ts->ttis[1];
468  }
469  }
470  }
471  if (sp->timecnt > 1)
472  {
473  for (i = 1; i < sp->timecnt; ++i)
474  if (typesequiv(sp, sp->types[i], sp->types[0]) &&
475  differ_by_repeat(sp->ats[i], sp->ats[0]))
476  {
477  sp->goback = true;
478  break;
479  }
480  for (i = sp->timecnt - 2; i >= 0; --i)
481  if (typesequiv(sp, sp->types[sp->timecnt - 1],
482  sp->types[i]) &&
483  differ_by_repeat(sp->ats[sp->timecnt - 1],
484  sp->ats[i]))
485  {
486  sp->goahead = true;
487  break;
488  }
489  }
490 
491  /*
492  * If type 0 is unused in transitions, it's the type to use for early
493  * times.
494  */
495  for (i = 0; i < sp->timecnt; ++i)
496  if (sp->types[i] == 0)
497  break;
498  i = i < sp->timecnt ? -1 : 0;
499 
500  /*
501  * Absent the above, if there are transition times and the first
502  * transition is to a daylight time find the standard type less than and
503  * closest to the type of the first transition.
504  */
505  if (i < 0 && sp->timecnt > 0 && sp->ttis[sp->types[0]].tt_isdst)
506  {
507  i = sp->types[0];
508  while (--i >= 0)
509  if (!sp->ttis[i].tt_isdst)
510  break;
511  }
512 
513  /*
514  * If no result yet, find the first standard type. If there is none, punt
515  * to type zero.
516  */
517  if (i < 0)
518  {
519  i = 0;
520  while (sp->ttis[i].tt_isdst)
521  if (++i >= sp->typecnt)
522  {
523  i = 0;
524  break;
525  }
526  }
527  sp->defaulttype = i;
528  return 0;
529 }
530 
531 /* Load tz data from the file named NAME into *SP. Read extended
532  * format if DOEXTEND. Return 0 on success, an errno value on failure.
533  * PG: If "canonname" is not NULL, then on success the canonical spelling of
534  * given name is stored there (the buffer must be > TZ_STRLEN_MAX bytes!).
535  */
536 int
537 tzload(const char *name, char *canonname, struct state * sp, bool doextend)
538 {
539  union local_storage *lsp = malloc(sizeof *lsp);
540 
541  if (!lsp)
542  return errno;
543  else
544  {
545  int err = tzloadbody(name, canonname, sp, doextend, lsp);
546 
547  free(lsp);
548  return err;
549  }
550 }
551 
552 static bool
553 typesequiv(const struct state * sp, int a, int b)
554 {
555  bool result;
556 
557  if (sp == NULL ||
558  a < 0 || a >= sp->typecnt ||
559  b < 0 || b >= sp->typecnt)
560  result = false;
561  else
562  {
563  const struct ttinfo *ap = &sp->ttis[a];
564  const struct ttinfo *bp = &sp->ttis[b];
565 
566  result = ap->tt_gmtoff == bp->tt_gmtoff &&
567  ap->tt_isdst == bp->tt_isdst &&
568  ap->tt_ttisstd == bp->tt_ttisstd &&
569  ap->tt_ttisgmt == bp->tt_ttisgmt &&
570  strcmp(&sp->chars[ap->tt_abbrind],
571  &sp->chars[bp->tt_abbrind]) == 0;
572  }
573  return result;
574 }
575 
576 static const int mon_lengths[2][MONSPERYEAR] = {
577  {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
578  {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
579 };
580 
581 static const int year_lengths[2] = {
583 };
584 
585 /*
586  * Given a pointer into a time zone string, scan until a character that is not
587  * a valid character in a zone name is found. Return a pointer to that
588  * character.
589  */
590 static const char *
591 getzname(const char *strp)
592 {
593  char c;
594 
595  while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
596  c != '+')
597  ++strp;
598  return strp;
599 }
600 
601 /*
602  * Given a pointer into an extended time zone string, scan until the ending
603  * delimiter of the zone name is located. Return a pointer to the delimiter.
604  *
605  * As with getzname above, the legal character set is actually quite
606  * restricted, with other characters producing undefined results.
607  * We don't do any checking here; checking is done later in common-case code.
608  */
609 static const char *
610 getqzname(const char *strp, int delim)
611 {
612  int c;
613 
614  while ((c = *strp) != '\0' && c != delim)
615  ++strp;
616  return strp;
617 }
618 
619 /*
620  * Given a pointer into a time zone string, extract a number from that string.
621  * Check that the number is within a specified range; if it is not, return
622  * NULL.
623  * Otherwise, return a pointer to the first character not part of the number.
624  */
625 static const char *
626 getnum(const char *strp, int *nump, int min, int max)
627 {
628  char c;
629  int num;
630 
631  if (strp == NULL || !is_digit(c = *strp))
632  return NULL;
633  num = 0;
634  do
635  {
636  num = num * 10 + (c - '0');
637  if (num > max)
638  return NULL; /* illegal value */
639  c = *++strp;
640  } while (is_digit(c));
641  if (num < min)
642  return NULL; /* illegal value */
643  *nump = num;
644  return strp;
645 }
646 
647 /*
648  * Given a pointer into a time zone string, extract a number of seconds,
649  * in hh[:mm[:ss]] form, from the string.
650  * If any error occurs, return NULL.
651  * Otherwise, return a pointer to the first character not part of the number
652  * of seconds.
653  */
654 static const char *
655 getsecs(const char *strp, int32 *secsp)
656 {
657  int num;
658 
659  /*
660  * 'HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
661  * "M10.4.6/26", which does not conform to Posix, but which specifies the
662  * equivalent of "02:00 on the first Sunday on or after 23 Oct".
663  */
664  strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
665  if (strp == NULL)
666  return NULL;
667  *secsp = num * (int32) SECSPERHOUR;
668  if (*strp == ':')
669  {
670  ++strp;
671  strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
672  if (strp == NULL)
673  return NULL;
674  *secsp += num * SECSPERMIN;
675  if (*strp == ':')
676  {
677  ++strp;
678  /* 'SECSPERMIN' allows for leap seconds. */
679  strp = getnum(strp, &num, 0, SECSPERMIN);
680  if (strp == NULL)
681  return NULL;
682  *secsp += num;
683  }
684  }
685  return strp;
686 }
687 
688 /*
689  * Given a pointer into a time zone string, extract an offset, in
690  * [+-]hh[:mm[:ss]] form, from the string.
691  * If any error occurs, return NULL.
692  * Otherwise, return a pointer to the first character not part of the time.
693  */
694 static const char *
695 getoffset(const char *strp, int32 *offsetp)
696 {
697  bool neg = false;
698 
699  if (*strp == '-')
700  {
701  neg = true;
702  ++strp;
703  }
704  else if (*strp == '+')
705  ++strp;
706  strp = getsecs(strp, offsetp);
707  if (strp == NULL)
708  return NULL; /* illegal time */
709  if (neg)
710  *offsetp = -*offsetp;
711  return strp;
712 }
713 
714 /*
715  * Given a pointer into a time zone string, extract a rule in the form
716  * date[/time]. See POSIX section 8 for the format of "date" and "time".
717  * If a valid rule is not found, return NULL.
718  * Otherwise, return a pointer to the first character not part of the rule.
719  */
720 static const char *
721 getrule(const char *strp, struct rule * rulep)
722 {
723  if (*strp == 'J')
724  {
725  /*
726  * Julian day.
727  */
728  rulep->r_type = JULIAN_DAY;
729  ++strp;
730  strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
731  }
732  else if (*strp == 'M')
733  {
734  /*
735  * Month, week, day.
736  */
737  rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
738  ++strp;
739  strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
740  if (strp == NULL)
741  return NULL;
742  if (*strp++ != '.')
743  return NULL;
744  strp = getnum(strp, &rulep->r_week, 1, 5);
745  if (strp == NULL)
746  return NULL;
747  if (*strp++ != '.')
748  return NULL;
749  strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
750  }
751  else if (is_digit(*strp))
752  {
753  /*
754  * Day of year.
755  */
756  rulep->r_type = DAY_OF_YEAR;
757  strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
758  }
759  else
760  return NULL; /* invalid format */
761  if (strp == NULL)
762  return NULL;
763  if (*strp == '/')
764  {
765  /*
766  * Time specified.
767  */
768  ++strp;
769  strp = getoffset(strp, &rulep->r_time);
770  }
771  else
772  rulep->r_time = 2 * SECSPERHOUR; /* default = 2:00:00 */
773  return strp;
774 }
775 
776 /*
777  * Given a year, a rule, and the offset from UT at the time that rule takes
778  * effect, calculate the year-relative time that rule takes effect.
779  */
780 static int32
781 transtime(int year, const struct rule * rulep,
782  int32 offset)
783 {
784  bool leapyear;
785  int32 value;
786  int i,
787  d,
788  m1,
789  yy0,
790  yy1,
791  yy2,
792  dow;
793 
794  INITIALIZE(value);
795  leapyear = isleap(year);
796  switch (rulep->r_type)
797  {
798 
799  case JULIAN_DAY:
800 
801  /*
802  * Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
803  * years. In non-leap years, or if the day number is 59 or less,
804  * just add SECSPERDAY times the day number-1 to the time of
805  * January 1, midnight, to get the day.
806  */
807  value = (rulep->r_day - 1) * SECSPERDAY;
808  if (leapyear && rulep->r_day >= 60)
809  value += SECSPERDAY;
810  break;
811 
812  case DAY_OF_YEAR:
813 
814  /*
815  * n - day of year. Just add SECSPERDAY times the day number to
816  * the time of January 1, midnight, to get the day.
817  */
818  value = rulep->r_day * SECSPERDAY;
819  break;
820 
822 
823  /*
824  * Mm.n.d - nth "dth day" of month m.
825  */
826 
827  /*
828  * Use Zeller's Congruence to get day-of-week of first day of
829  * month.
830  */
831  m1 = (rulep->r_mon + 9) % 12 + 1;
832  yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
833  yy1 = yy0 / 100;
834  yy2 = yy0 % 100;
835  dow = ((26 * m1 - 2) / 10 +
836  1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
837  if (dow < 0)
838  dow += DAYSPERWEEK;
839 
840  /*
841  * "dow" is the day-of-week of the first day of the month. Get the
842  * day-of-month (zero-origin) of the first "dow" day of the month.
843  */
844  d = rulep->r_day - dow;
845  if (d < 0)
846  d += DAYSPERWEEK;
847  for (i = 1; i < rulep->r_week; ++i)
848  {
849  if (d + DAYSPERWEEK >=
850  mon_lengths[(int) leapyear][rulep->r_mon - 1])
851  break;
852  d += DAYSPERWEEK;
853  }
854 
855  /*
856  * "d" is the day-of-month (zero-origin) of the day we want.
857  */
858  value = d * SECSPERDAY;
859  for (i = 0; i < rulep->r_mon - 1; ++i)
860  value += mon_lengths[(int) leapyear][i] * SECSPERDAY;
861  break;
862  }
863 
864  /*
865  * "value" is the year-relative time of 00:00:00 UT on the day in
866  * question. To get the year-relative time of the specified local time on
867  * that day, add the transition time and the current offset from UT.
868  */
869  return value + rulep->r_time + offset;
870 }
871 
872 /*
873  * Given a POSIX section 8-style TZ string, fill in the rule tables as
874  * appropriate.
875  * Returns true on success, false on failure.
876  */
877 bool
878 tzparse(const char *name, struct state * sp, bool lastditch)
879 {
880  const char *stdname;
881  const char *dstname = NULL;
882  size_t stdlen;
883  size_t dstlen;
884  size_t charcnt;
885  int32 stdoffset;
886  int32 dstoffset;
887  char *cp;
888  bool load_ok;
889 
890  stdname = name;
891  if (lastditch)
892  {
893  /*
894  * This is intentionally somewhat different from the IANA code. We do
895  * not want to invoke tzload() in the lastditch case: we can't assume
896  * pg_open_tzfile() is sane yet, and we don't care about leap seconds
897  * anyway.
898  */
899  stdlen = strlen(name); /* length of standard zone name */
900  name += stdlen;
901  if (stdlen >= sizeof sp->chars)
902  stdlen = (sizeof sp->chars) - 1;
903  charcnt = stdlen + 1;
904  stdoffset = 0;
905  sp->goback = sp->goahead = false; /* simulate failed tzload() */
906  load_ok = false;
907  }
908  else
909  {
910  if (*name == '<')
911  {
912  name++;
913  stdname = name;
914  name = getqzname(name, '>');
915  if (*name != '>')
916  return false;
917  stdlen = name - stdname;
918  name++;
919  }
920  else
921  {
922  name = getzname(name);
923  stdlen = name - stdname;
924  }
925  if (*name == '\0') /* we allow empty STD abbrev, unlike IANA */
926  return false;
927  name = getoffset(name, &stdoffset);
928  if (name == NULL)
929  return false;
930  charcnt = stdlen + 1;
931  if (sizeof sp->chars < charcnt)
932  return false;
933  load_ok = tzload(TZDEFRULES, NULL, sp, false) == 0;
934  }
935  if (!load_ok)
936  sp->leapcnt = 0; /* so, we're off a little */
937  if (*name != '\0')
938  {
939  if (*name == '<')
940  {
941  dstname = ++name;
942  name = getqzname(name, '>');
943  if (*name != '>')
944  return false;
945  dstlen = name - dstname;
946  name++;
947  }
948  else
949  {
950  dstname = name;
951  name = getzname(name);
952  dstlen = name - dstname; /* length of DST zone name */
953  }
954  if (!dstlen)
955  return false;
956  charcnt += dstlen + 1;
957  if (sizeof sp->chars < charcnt)
958  return false;
959  if (*name != '\0' && *name != ',' && *name != ';')
960  {
961  name = getoffset(name, &dstoffset);
962  if (name == NULL)
963  return false;
964  }
965  else
966  dstoffset = stdoffset - SECSPERHOUR;
967  if (*name == '\0' && !load_ok)
968  name = TZDEFRULESTRING;
969  if (*name == ',' || *name == ';')
970  {
971  struct rule start;
972  struct rule end;
973  int year;
974  int yearlim;
975  int timecnt;
976  pg_time_t janfirst;
977 
978  ++name;
979  if ((name = getrule(name, &start)) == NULL)
980  return false;
981  if (*name++ != ',')
982  return false;
983  if ((name = getrule(name, &end)) == NULL)
984  return false;
985  if (*name != '\0')
986  return false;
987  sp->typecnt = 2; /* standard time and DST */
988 
989  /*
990  * Two transitions per year, from EPOCH_YEAR forward.
991  */
992  init_ttinfo(&sp->ttis[0], -dstoffset, true, stdlen + 1);
993  init_ttinfo(&sp->ttis[1], -stdoffset, false, 0);
994  sp->defaulttype = 0;
995  timecnt = 0;
996  janfirst = 0;
997  yearlim = EPOCH_YEAR + YEARSPERREPEAT;
998  for (year = EPOCH_YEAR; year < yearlim; year++)
999  {
1000  int32
1001  starttime = transtime(year, &start, stdoffset),
1002  endtime = transtime(year, &end, dstoffset);
1003  int32
1004  yearsecs = (year_lengths[isleap(year)]
1005  * SECSPERDAY);
1006  bool reversed = endtime < starttime;
1007 
1008  if (reversed)
1009  {
1010  int32 swap = starttime;
1011 
1012  starttime = endtime;
1013  endtime = swap;
1014  }
1015  if (reversed
1016  || (starttime < endtime
1017  && (endtime - starttime
1018  < (yearsecs
1019  + (stdoffset - dstoffset)))))
1020  {
1021  if (TZ_MAX_TIMES - 2 < timecnt)
1022  break;
1023  yearlim = year + YEARSPERREPEAT + 1;
1024  sp->ats[timecnt] = janfirst;
1026  (&sp->ats[timecnt], starttime))
1027  break;
1028  sp->types[timecnt++] = reversed;
1029  sp->ats[timecnt] = janfirst;
1031  (&sp->ats[timecnt], endtime))
1032  break;
1033  sp->types[timecnt++] = !reversed;
1034  }
1035  if (increment_overflow_time(&janfirst, yearsecs))
1036  break;
1037  }
1038  sp->timecnt = timecnt;
1039  if (!timecnt)
1040  sp->typecnt = 1; /* Perpetual DST. */
1041  }
1042  else
1043  {
1044  int32 theirstdoffset;
1045  int32 theirdstoffset;
1046  int32 theiroffset;
1047  bool isdst;
1048  int i;
1049  int j;
1050 
1051  if (*name != '\0')
1052  return false;
1053 
1054  /*
1055  * Initial values of theirstdoffset and theirdstoffset.
1056  */
1057  theirstdoffset = 0;
1058  for (i = 0; i < sp->timecnt; ++i)
1059  {
1060  j = sp->types[i];
1061  if (!sp->ttis[j].tt_isdst)
1062  {
1063  theirstdoffset =
1064  -sp->ttis[j].tt_gmtoff;
1065  break;
1066  }
1067  }
1068  theirdstoffset = 0;
1069  for (i = 0; i < sp->timecnt; ++i)
1070  {
1071  j = sp->types[i];
1072  if (sp->ttis[j].tt_isdst)
1073  {
1074  theirdstoffset =
1075  -sp->ttis[j].tt_gmtoff;
1076  break;
1077  }
1078  }
1079 
1080  /*
1081  * Initially we're assumed to be in standard time.
1082  */
1083  isdst = false;
1084  theiroffset = theirstdoffset;
1085 
1086  /*
1087  * Now juggle transition times and types tracking offsets as you
1088  * do.
1089  */
1090  for (i = 0; i < sp->timecnt; ++i)
1091  {
1092  j = sp->types[i];
1093  sp->types[i] = sp->ttis[j].tt_isdst;
1094  if (sp->ttis[j].tt_ttisgmt)
1095  {
1096  /* No adjustment to transition time */
1097  }
1098  else
1099  {
1100  /*
1101  * If summer time is in effect, and the transition time
1102  * was not specified as standard time, add the summer time
1103  * offset to the transition time; otherwise, add the
1104  * standard time offset to the transition time.
1105  */
1106 
1107  /*
1108  * Transitions from DST to DDST will effectively disappear
1109  * since POSIX provides for only one DST offset.
1110  */
1111  if (isdst && !sp->ttis[j].tt_ttisstd)
1112  {
1113  sp->ats[i] += dstoffset -
1114  theirdstoffset;
1115  }
1116  else
1117  {
1118  sp->ats[i] += stdoffset -
1119  theirstdoffset;
1120  }
1121  }
1122  theiroffset = -sp->ttis[j].tt_gmtoff;
1123  if (sp->ttis[j].tt_isdst)
1124  theirdstoffset = theiroffset;
1125  else
1126  theirstdoffset = theiroffset;
1127  }
1128 
1129  /*
1130  * Finally, fill in ttis.
1131  */
1132  init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
1133  init_ttinfo(&sp->ttis[1], -dstoffset, true, stdlen + 1);
1134  sp->typecnt = 2;
1135  sp->defaulttype = 0;
1136  }
1137  }
1138  else
1139  {
1140  dstlen = 0;
1141  sp->typecnt = 1; /* only standard time */
1142  sp->timecnt = 0;
1143  init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
1144  sp->defaulttype = 0;
1145  }
1146  sp->charcnt = charcnt;
1147  cp = sp->chars;
1148  memcpy(cp, stdname, stdlen);
1149  cp += stdlen;
1150  *cp++ = '\0';
1151  if (dstlen != 0)
1152  {
1153  memcpy(cp, dstname, dstlen);
1154  *(cp + dstlen) = '\0';
1155  }
1156  return true;
1157 }
1158 
1159 static void
1160 gmtload(struct state * sp)
1161 {
1162  if (tzload(gmt, NULL, sp, true) != 0)
1163  tzparse(gmt, sp, true);
1164 }
1165 
1166 
1167 /*
1168  * The easy way to behave "as if no library function calls" localtime
1169  * is to not call it, so we drop its guts into "localsub", which can be
1170  * freely called. (And no, the PANS doesn't require the above behavior,
1171  * but it *is* desirable.)
1172  */
1173 static struct pg_tm *
1174 localsub(struct state const * sp, pg_time_t const * timep,
1175  struct pg_tm * tmp)
1176 {
1177  const struct ttinfo *ttisp;
1178  int i;
1179  struct pg_tm *result;
1180  const pg_time_t t = *timep;
1181 
1182  if (sp == NULL)
1183  return gmtsub(timep, 0, tmp);
1184  if ((sp->goback && t < sp->ats[0]) ||
1185  (sp->goahead && t > sp->ats[sp->timecnt - 1]))
1186  {
1187  pg_time_t newt = t;
1188  pg_time_t seconds;
1189  pg_time_t years;
1190 
1191  if (t < sp->ats[0])
1192  seconds = sp->ats[0] - t;
1193  else
1194  seconds = t - sp->ats[sp->timecnt - 1];
1195  --seconds;
1196  years = (seconds / SECSPERREPEAT + 1) * YEARSPERREPEAT;
1197  seconds = years * AVGSECSPERYEAR;
1198  if (t < sp->ats[0])
1199  newt += seconds;
1200  else
1201  newt -= seconds;
1202  if (newt < sp->ats[0] ||
1203  newt > sp->ats[sp->timecnt - 1])
1204  return NULL; /* "cannot happen" */
1205  result = localsub(sp, &newt, tmp);
1206  if (result)
1207  {
1208  int64 newy;
1209 
1210  newy = result->tm_year;
1211  if (t < sp->ats[0])
1212  newy -= years;
1213  else
1214  newy += years;
1215  if (!(INT_MIN <= newy && newy <= INT_MAX))
1216  return NULL;
1217  result->tm_year = newy;
1218  }
1219  return result;
1220  }
1221  if (sp->timecnt == 0 || t < sp->ats[0])
1222  {
1223  i = sp->defaulttype;
1224  }
1225  else
1226  {
1227  int lo = 1;
1228  int hi = sp->timecnt;
1229 
1230  while (lo < hi)
1231  {
1232  int mid = (lo + hi) >> 1;
1233 
1234  if (t < sp->ats[mid])
1235  hi = mid;
1236  else
1237  lo = mid + 1;
1238  }
1239  i = (int) sp->types[lo - 1];
1240  }
1241  ttisp = &sp->ttis[i];
1242 
1243  result = timesub(&t, ttisp->tt_gmtoff, sp, tmp);
1244  if (result)
1245  {
1246  result->tm_isdst = ttisp->tt_isdst;
1247  result->tm_zone = (char *) &sp->chars[ttisp->tt_abbrind];
1248  }
1249  return result;
1250 }
1251 
1252 
1253 struct pg_tm *
1254 pg_localtime(const pg_time_t *timep, const pg_tz *tz)
1255 {
1256  return localsub(&tz->state, timep, &tm);
1257 }
1258 
1259 
1260 /*
1261  * gmtsub is to gmtime as localsub is to localtime.
1262  *
1263  * Except we have a private "struct state" for GMT, so no sp is passed in.
1264  */
1265 static struct pg_tm *
1266 gmtsub(pg_time_t const * timep, int32 offset, struct pg_tm * tmp)
1267 {
1268  struct pg_tm *result;
1269 
1270  /* GMT timezone state data is kept here */
1271  static struct state gmtmem;
1272  static bool gmt_is_set = false;
1273 #define gmtptr (&gmtmem)
1274 
1275  if (!gmt_is_set)
1276  {
1277  gmt_is_set = true;
1278  gmtload(gmtptr);
1279  }
1280  result = timesub(timep, offset, gmtptr, tmp);
1281 
1282  /*
1283  * Could get fancy here and deliver something such as "+xx" or "-xx" if
1284  * offset is non-zero, but this is no time for a treasure hunt.
1285  */
1286  if (offset != 0)
1287  tmp->tm_zone = wildabbr;
1288  else
1289  tmp->tm_zone = gmtptr->chars;
1290 
1291  return result;
1292 }
1293 
1294 struct pg_tm *
1295 pg_gmtime(const pg_time_t *timep)
1296 {
1297  return gmtsub(timep, 0, &tm);
1298 }
1299 
1300 /*
1301  * Return the number of leap years through the end of the given year
1302  * where, to make the math easy, the answer for year zero is defined as zero.
1303  */
1304 static int
1305 leaps_thru_end_of(const int y)
1306 {
1307  return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
1308  -(leaps_thru_end_of(-(y + 1)) + 1);
1309 }
1310 
1311 static struct pg_tm *
1312 timesub(const pg_time_t *timep, int32 offset,
1313  const struct state * sp, struct pg_tm * tmp)
1314 {
1315  const struct lsinfo *lp;
1316  pg_time_t tdays;
1317  int idays; /* unsigned would be so 2003 */
1318  int64 rem;
1319  int y;
1320  const int *ip;
1321  int64 corr;
1322  bool hit;
1323  int i;
1324 
1325  corr = 0;
1326  hit = false;
1327  i = (sp == NULL) ? 0 : sp->leapcnt;
1328  while (--i >= 0)
1329  {
1330  lp = &sp->lsis[i];
1331  if (*timep >= lp->ls_trans)
1332  {
1333  if (*timep == lp->ls_trans)
1334  {
1335  hit = ((i == 0 && lp->ls_corr > 0) ||
1336  lp->ls_corr > sp->lsis[i - 1].ls_corr);
1337  if (hit)
1338  while (i > 0 &&
1339  sp->lsis[i].ls_trans ==
1340  sp->lsis[i - 1].ls_trans + 1 &&
1341  sp->lsis[i].ls_corr ==
1342  sp->lsis[i - 1].ls_corr + 1)
1343  {
1344  ++hit;
1345  --i;
1346  }
1347  }
1348  corr = lp->ls_corr;
1349  break;
1350  }
1351  }
1352  y = EPOCH_YEAR;
1353  tdays = *timep / SECSPERDAY;
1354  rem = *timep % SECSPERDAY;
1355  while (tdays < 0 || tdays >= year_lengths[isleap(y)])
1356  {
1357  int newy;
1358  pg_time_t tdelta;
1359  int idelta;
1360  int leapdays;
1361 
1362  tdelta = tdays / DAYSPERLYEAR;
1363  if (!((!TYPE_SIGNED(pg_time_t) ||INT_MIN <= tdelta)
1364  && tdelta <= INT_MAX))
1365  goto out_of_range;
1366  idelta = tdelta;
1367  if (idelta == 0)
1368  idelta = (tdays < 0) ? -1 : 1;
1369  newy = y;
1370  if (increment_overflow(&newy, idelta))
1371  goto out_of_range;
1372  leapdays = leaps_thru_end_of(newy - 1) -
1373  leaps_thru_end_of(y - 1);
1374  tdays -= ((pg_time_t) newy - y) * DAYSPERNYEAR;
1375  tdays -= leapdays;
1376  y = newy;
1377  }
1378 
1379  /*
1380  * Given the range, we can now fearlessly cast...
1381  */
1382  idays = tdays;
1383  rem += offset - corr;
1384  while (rem < 0)
1385  {
1386  rem += SECSPERDAY;
1387  --idays;
1388  }
1389  while (rem >= SECSPERDAY)
1390  {
1391  rem -= SECSPERDAY;
1392  ++idays;
1393  }
1394  while (idays < 0)
1395  {
1396  if (increment_overflow(&y, -1))
1397  goto out_of_range;
1398  idays += year_lengths[isleap(y)];
1399  }
1400  while (idays >= year_lengths[isleap(y)])
1401  {
1402  idays -= year_lengths[isleap(y)];
1403  if (increment_overflow(&y, 1))
1404  goto out_of_range;
1405  }
1406  tmp->tm_year = y;
1408  goto out_of_range;
1409  tmp->tm_yday = idays;
1410 
1411  /*
1412  * The "extra" mods below avoid overflow problems.
1413  */
1414  tmp->tm_wday = EPOCH_WDAY +
1415  ((y - EPOCH_YEAR) % DAYSPERWEEK) *
1417  leaps_thru_end_of(y - 1) -
1419  idays;
1420  tmp->tm_wday %= DAYSPERWEEK;
1421  if (tmp->tm_wday < 0)
1422  tmp->tm_wday += DAYSPERWEEK;
1423  tmp->tm_hour = (int) (rem / SECSPERHOUR);
1424  rem %= SECSPERHOUR;
1425  tmp->tm_min = (int) (rem / SECSPERMIN);
1426 
1427  /*
1428  * A positive leap second requires a special representation. This uses
1429  * "... ??:59:60" et seq.
1430  */
1431  tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1432  ip = mon_lengths[isleap(y)];
1433  for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
1434  idays -= ip[tmp->tm_mon];
1435  tmp->tm_mday = (int) (idays + 1);
1436  tmp->tm_isdst = 0;
1437  tmp->tm_gmtoff = offset;
1438  return tmp;
1439 
1440 out_of_range:
1441  errno = EOVERFLOW;
1442  return NULL;
1443 }
1444 
1445 /*
1446  * Normalize logic courtesy Paul Eggert.
1447  */
1448 
1449 static bool
1450 increment_overflow(int *ip, int j)
1451 {
1452  int const i = *ip;
1453 
1454  /*----------
1455  * If i >= 0 there can only be overflow if i + j > INT_MAX
1456  * or if j > INT_MAX - i; given i >= 0, INT_MAX - i cannot overflow.
1457  * If i < 0 there can only be overflow if i + j < INT_MIN
1458  * or if j < INT_MIN - i; given i < 0, INT_MIN - i cannot overflow.
1459  *----------
1460  */
1461  if ((i >= 0) ? (j > INT_MAX - i) : (j < INT_MIN - i))
1462  return true;
1463  *ip += j;
1464  return false;
1465 }
1466 
1467 static bool
1469 {
1470  /*----------
1471  * This is like
1472  * 'if (! (time_t_min <= *tp + j && *tp + j <= time_t_max)) ...',
1473  * except that it does the right thing even if *tp + j would overflow.
1474  *----------
1475  */
1476  if (!(j < 0
1477  ? (TYPE_SIGNED(pg_time_t) ? time_t_min - j <= *tp : -1 - j < *tp)
1478  : *tp <= time_t_max - j))
1479  return true;
1480  *tp += j;
1481  return false;
1482 }
1483 
1484 /*
1485  * Find the next DST transition time in the given zone after the given time
1486  *
1487  * *timep and *tz are input arguments, the other parameters are output values.
1488  *
1489  * When the function result is 1, *boundary is set to the pg_time_t
1490  * representation of the next DST transition time after *timep,
1491  * *before_gmtoff and *before_isdst are set to the GMT offset and isdst
1492  * state prevailing just before that boundary (in particular, the state
1493  * prevailing at *timep), and *after_gmtoff and *after_isdst are set to
1494  * the state prevailing just after that boundary.
1495  *
1496  * When the function result is 0, there is no known DST transition
1497  * after *timep, but *before_gmtoff and *before_isdst indicate the GMT
1498  * offset and isdst state prevailing at *timep. (This would occur in
1499  * DST-less time zones, or if a zone has permanently ceased using DST.)
1500  *
1501  * A function result of -1 indicates failure (this case does not actually
1502  * occur in our current implementation).
1503  */
1504 int
1506  long int *before_gmtoff,
1507  int *before_isdst,
1508  pg_time_t *boundary,
1509  long int *after_gmtoff,
1510  int *after_isdst,
1511  const pg_tz *tz)
1512 {
1513  const struct state *sp;
1514  const struct ttinfo *ttisp;
1515  int i;
1516  int j;
1517  const pg_time_t t = *timep;
1518 
1519  sp = &tz->state;
1520  if (sp->timecnt == 0)
1521  {
1522  /* non-DST zone, use lowest-numbered standard type */
1523  i = 0;
1524  while (sp->ttis[i].tt_isdst)
1525  if (++i >= sp->typecnt)
1526  {
1527  i = 0;
1528  break;
1529  }
1530  ttisp = &sp->ttis[i];
1531  *before_gmtoff = ttisp->tt_gmtoff;
1532  *before_isdst = ttisp->tt_isdst;
1533  return 0;
1534  }
1535  if ((sp->goback && t < sp->ats[0]) ||
1536  (sp->goahead && t > sp->ats[sp->timecnt - 1]))
1537  {
1538  /* For values outside the transition table, extrapolate */
1539  pg_time_t newt = t;
1540  pg_time_t seconds;
1541  pg_time_t tcycles;
1542  int64 icycles;
1543  int result;
1544 
1545  if (t < sp->ats[0])
1546  seconds = sp->ats[0] - t;
1547  else
1548  seconds = t - sp->ats[sp->timecnt - 1];
1549  --seconds;
1550  tcycles = seconds / YEARSPERREPEAT / AVGSECSPERYEAR;
1551  ++tcycles;
1552  icycles = tcycles;
1553  if (tcycles - icycles >= 1 || icycles - tcycles >= 1)
1554  return -1;
1555  seconds = icycles;
1556  seconds *= YEARSPERREPEAT;
1557  seconds *= AVGSECSPERYEAR;
1558  if (t < sp->ats[0])
1559  newt += seconds;
1560  else
1561  newt -= seconds;
1562  if (newt < sp->ats[0] ||
1563  newt > sp->ats[sp->timecnt - 1])
1564  return -1; /* "cannot happen" */
1565 
1566  result = pg_next_dst_boundary(&newt, before_gmtoff,
1567  before_isdst,
1568  boundary,
1569  after_gmtoff,
1570  after_isdst,
1571  tz);
1572  if (t < sp->ats[0])
1573  *boundary -= seconds;
1574  else
1575  *boundary += seconds;
1576  return result;
1577  }
1578 
1579  if (t >= sp->ats[sp->timecnt - 1])
1580  {
1581  /* No known transition > t, so use last known segment's type */
1582  i = sp->types[sp->timecnt - 1];
1583  ttisp = &sp->ttis[i];
1584  *before_gmtoff = ttisp->tt_gmtoff;
1585  *before_isdst = ttisp->tt_isdst;
1586  return 0;
1587  }
1588  if (t < sp->ats[0])
1589  {
1590  /* For "before", use lowest-numbered standard type */
1591  i = 0;
1592  while (sp->ttis[i].tt_isdst)
1593  if (++i >= sp->typecnt)
1594  {
1595  i = 0;
1596  break;
1597  }
1598  ttisp = &sp->ttis[i];
1599  *before_gmtoff = ttisp->tt_gmtoff;
1600  *before_isdst = ttisp->tt_isdst;
1601  *boundary = sp->ats[0];
1602  /* And for "after", use the first segment's type */
1603  i = sp->types[0];
1604  ttisp = &sp->ttis[i];
1605  *after_gmtoff = ttisp->tt_gmtoff;
1606  *after_isdst = ttisp->tt_isdst;
1607  return 1;
1608  }
1609  /* Else search to find the boundary following t */
1610  {
1611  int lo = 1;
1612  int hi = sp->timecnt - 1;
1613 
1614  while (lo < hi)
1615  {
1616  int mid = (lo + hi) >> 1;
1617 
1618  if (t < sp->ats[mid])
1619  hi = mid;
1620  else
1621  lo = mid + 1;
1622  }
1623  i = lo;
1624  }
1625  j = sp->types[i - 1];
1626  ttisp = &sp->ttis[j];
1627  *before_gmtoff = ttisp->tt_gmtoff;
1628  *before_isdst = ttisp->tt_isdst;
1629  *boundary = sp->ats[i];
1630  j = sp->types[i];
1631  ttisp = &sp->ttis[j];
1632  *after_gmtoff = ttisp->tt_gmtoff;
1633  *after_isdst = ttisp->tt_isdst;
1634  return 1;
1635 }
1636 
1637 /*
1638  * Identify a timezone abbreviation's meaning in the given zone
1639  *
1640  * Determine the GMT offset and DST flag associated with the abbreviation.
1641  * This is generally used only when the abbreviation has actually changed
1642  * meaning over time; therefore, we also take a UTC cutoff time, and return
1643  * the meaning in use at or most recently before that time, or the meaning
1644  * in first use after that time if the abbrev was never used before that.
1645  *
1646  * On success, returns true and sets *gmtoff and *isdst. If the abbreviation
1647  * was never used at all in this zone, returns false.
1648  *
1649  * Note: abbrev is matched case-sensitively; it should be all-upper-case.
1650  */
1651 bool
1652 pg_interpret_timezone_abbrev(const char *abbrev,
1653  const pg_time_t *timep,
1654  long int *gmtoff,
1655  int *isdst,
1656  const pg_tz *tz)
1657 {
1658  const struct state *sp;
1659  const char *abbrs;
1660  const struct ttinfo *ttisp;
1661  int abbrind;
1662  int cutoff;
1663  int i;
1664  const pg_time_t t = *timep;
1665 
1666  sp = &tz->state;
1667 
1668  /*
1669  * Locate the abbreviation in the zone's abbreviation list. We assume
1670  * there are not duplicates in the list.
1671  */
1672  abbrs = sp->chars;
1673  abbrind = 0;
1674  while (abbrind < sp->charcnt)
1675  {
1676  if (strcmp(abbrev, abbrs + abbrind) == 0)
1677  break;
1678  while (abbrs[abbrind] != '\0')
1679  abbrind++;
1680  abbrind++;
1681  }
1682  if (abbrind >= sp->charcnt)
1683  return false; /* not there! */
1684 
1685  /*
1686  * Unlike pg_next_dst_boundary, we needn't sweat about extrapolation
1687  * (goback/goahead zones). Finding the newest or oldest meaning of the
1688  * abbreviation should get us what we want, since extrapolation would just
1689  * be repeating the newest or oldest meanings.
1690  *
1691  * Use binary search to locate the first transition > cutoff time.
1692  */
1693  {
1694  int lo = 0;
1695  int hi = sp->timecnt;
1696 
1697  while (lo < hi)
1698  {
1699  int mid = (lo + hi) >> 1;
1700 
1701  if (t < sp->ats[mid])
1702  hi = mid;
1703  else
1704  lo = mid + 1;
1705  }
1706  cutoff = lo;
1707  }
1708 
1709  /*
1710  * Scan backwards to find the latest interval using the given abbrev
1711  * before the cutoff time.
1712  */
1713  for (i = cutoff - 1; i >= 0; i--)
1714  {
1715  ttisp = &sp->ttis[sp->types[i]];
1716  if (ttisp->tt_abbrind == abbrind)
1717  {
1718  *gmtoff = ttisp->tt_gmtoff;
1719  *isdst = ttisp->tt_isdst;
1720  return true;
1721  }
1722  }
1723 
1724  /*
1725  * Not there, so scan forwards to find the first one after.
1726  */
1727  for (i = cutoff; i < sp->timecnt; i++)
1728  {
1729  ttisp = &sp->ttis[sp->types[i]];
1730  if (ttisp->tt_abbrind == abbrind)
1731  {
1732  *gmtoff = ttisp->tt_gmtoff;
1733  *isdst = ttisp->tt_isdst;
1734  return true;
1735  }
1736  }
1737 
1738  return false; /* hm, not actually used in any interval? */
1739 }
1740 
1741 /*
1742  * If the given timezone uses only one GMT offset, store that offset
1743  * into *gmtoff and return true, else return false.
1744  */
1745 bool
1746 pg_get_timezone_offset(const pg_tz *tz, long int *gmtoff)
1747 {
1748  /*
1749  * The zone could have more than one ttinfo, if it's historically used
1750  * more than one abbreviation. We return true as long as they all have
1751  * the same gmtoff.
1752  */
1753  const struct state *sp;
1754  int i;
1755 
1756  sp = &tz->state;
1757  for (i = 1; i < sp->typecnt; i++)
1758  {
1759  if (sp->ttis[i].tt_gmtoff != sp->ttis[0].tt_gmtoff)
1760  return false;
1761  }
1762  *gmtoff = sp->ttis[0].tt_gmtoff;
1763  return true;
1764 }
1765 
1766 /*
1767  * Return the name of the current timezone
1768  */
1769 const char *
1771 {
1772  if (tz)
1773  return tz->TZname;
1774  return NULL;
1775 }
1776 
1777 /*
1778  * Check whether timezone is acceptable.
1779  *
1780  * What we are doing here is checking for leap-second-aware timekeeping.
1781  * We need to reject such TZ settings because they'll wreak havoc with our
1782  * date/time arithmetic.
1783  */
1784 bool
1786 {
1787  struct pg_tm *tt;
1788  pg_time_t time2000;
1789 
1790  /*
1791  * To detect leap-second timekeeping, run pg_localtime for what should be
1792  * GMT midnight, 2000-01-01. Insist that the tm_sec value be zero; any
1793  * other result has to be due to leap seconds.
1794  */
1796  tt = pg_localtime(&time2000, tz);
1797  if (!tt || tt->tm_sec != 0)
1798  return false;
1799 
1800  return true;
1801 }
#define AVGSECSPERYEAR
Definition: private.h:120
#define TZDEFAULT
Definition: tzfile.h:24
static void gmtload(struct state *sp)
Definition: localtime.c:1160
static struct @76 value
struct pg_tm * pg_localtime(const pg_time_t *timep, const pg_tz *tz)
Definition: localtime.c:1254
static int typecnt
Definition: zic.c:184
#define DAYSPERLYEAR
Definition: tzfile.h:108
#define swap(a, b)
Definition: qsort.c:94
static const char * getoffset(const char *strp, int32 *offsetp)
Definition: localtime.c:695
static void init_ttinfo(struct ttinfo *s, int32 gmtoff, bool isdst, int abbrind)
Definition: localtime.c:107
int64 pg_time_t
Definition: pgtime.h:23
int tm_wday
Definition: pgtime.h:33
bool pg_tz_acceptable(pg_tz *tz)
Definition: localtime.c:1785
#define DAYSPERNYEAR
Definition: tzfile.h:107
#define WILDABBR
Definition: localtime.c:45
int tm_isdst
Definition: pgtime.h:35
int tzload(const char *name, char *canonname, struct state *sp, bool doextend)
Definition: localtime.c:537
int charcnt
Definition: pgtz.h:46
static int32 detzcode(const char *codep)
Definition: localtime.c:117
int tm_hour
Definition: pgtime.h:29
#define EPOCH_WDAY
Definition: tzfile.h:137
static zic_t corr[TZ_MAX_LEAPS]
Definition: zic.c:383
bool goback
Definition: pgtz.h:47
static int tzloadbody(char const *name, char *canonname, struct state *sp, bool doextend, union local_storage *lsp)
Definition: localtime.c:210
int32 tt_gmtoff
Definition: pgtz.h:28
static const char * getsecs(const char *strp, int32 *secsp)
Definition: localtime.c:655
#define isleap(y)
Definition: datetime.h:273
int leapcnt
Definition: pgtz.h:43
#define INITIALIZE(x)
Definition: private.h:106
Definition: pgtz.h:26
static const char * getrule(const char *strp, struct rule *rulep)
Definition: localtime.c:721
static const int mon_lengths[2][MONSPERYEAR]
Definition: localtime.c:576
#define TZ_MAX_TIMES
Definition: tzfile.h:93
struct tzhead tzhead
Definition: localtime.c:180
char tzh_timecnt[4]
Definition: tzfile.h:41
long int tm_gmtoff
Definition: pgtime.h:36
Definition: pgtime.h:25
r_type
Definition: localtime.c:67
int r_mon
Definition: localtime.c:79
pg_time_t ats[TZ_MAX_TIMES]
Definition: pgtz.h:49
#define HOURSPERDAY
Definition: tzfile.h:105
#define TZDEFRULESTRING
Definition: localtime.c:63
#define is_digit(c)
Definition: private.h:49
Definition: localtime.c:74
signed int int32
Definition: c.h:253
static struct pg_tm tm
Definition: localtime.c:103
struct state st
Definition: localtime.c:199
#define malloc(a)
Definition: header.h:45
#define TZ_MAX_LEAPS
Definition: tzfile.h:101
int r_week
Definition: localtime.c:78
bool tt_isdst
Definition: pgtz.h:29
struct lsinfo lsis[TZ_MAX_LEAPS]
Definition: pgtz.h:54
static int64 detzcode64(const char *codep)
Definition: localtime.c:143
#define SECS_PER_DAY
Definition: timestamp.h:86
const char * pg_get_timezone_name(pg_tz *tz)
Definition: localtime.c:1770
#define SECSPERDAY
Definition: tzfile.h:110
static const pg_time_t time_t_max
Definition: localtime.c:54
int64 ls_corr
Definition: pgtz.h:38
#define MINVAL(t, b)
Definition: private.h:88
char * c
int tm_mday
Definition: pgtime.h:30
#define memmove(d, s, c)
Definition: c.h:1058
int tm_mon
Definition: pgtime.h:31
static const pg_time_t time_t_min
Definition: localtime.c:53
static const char wildabbr[]
Definition: localtime.c:48
static int leapcnt
Definition: zic.c:167
#define MONSPERYEAR
Definition: tzfile.h:111
#define SECSPERREPEAT_BITS
Definition: private.h:128
pg_time_t ls_trans
Definition: pgtz.h:37
char tzh_leapcnt[4]
Definition: tzfile.h:40
static bool typesequiv(struct state const *, int, int)
Definition: localtime.c:553
const char * tm_zone
Definition: pgtime.h:37
enum r_type r_type
Definition: localtime.c:76
int32 r_time
Definition: localtime.c:80
bool tzparse(const char *name, struct state *sp, bool lastditch)
Definition: localtime.c:878
char chars[BIGGEST(BIGGEST(TZ_MAX_CHARS+1, 3),(2 *(TZ_STRLEN_MAX+1)))]
Definition: pgtz.h:53
int r_day
Definition: localtime.c:77
static int32 transtime(int year, const struct rule *rulep, int32 offset)
Definition: localtime.c:781
#define TZ_MAX_CHARS
Definition: tzfile.h:98
char buf[2 *sizeof(struct tzhead)+2 *sizeof(struct state)+4 *TZ_MAX_TIMES]
Definition: localtime.c:184
struct state state
Definition: pgtz.h:63
Definition: pgtz.h:59
struct ttinfo ttis[TZ_MAX_TYPES]
Definition: pgtz.h:51
unsigned char types[TZ_MAX_TIMES]
Definition: pgtz.h:50
#define MINSPERHOUR
Definition: tzfile.h:104
Definition: tzfile.h:33
#define TM_YEAR_BASE
Definition: tzfile.h:134
int pg_next_dst_boundary(const pg_time_t *timep, long int *before_gmtoff, int *before_isdst, pg_time_t *boundary, long int *after_gmtoff, int *after_isdst, const pg_tz *tz)
Definition: localtime.c:1505
char tzh_typecnt[4]
Definition: tzfile.h:42
#define free(a)
Definition: header.h:60
char tzh_version[1]
Definition: tzfile.h:36
#define DAYSPERWEEK
Definition: tzfile.h:106
#define NULL
Definition: c.h:226
char tzh_charcnt[4]
Definition: tzfile.h:43
Definition: regguts.h:298
#define TZDEFRULES
Definition: tzfile.h:25
static ptrdiff_t timecnt
Definition: zic.c:182
int timecnt
Definition: pgtz.h:44
bool pg_get_timezone_offset(const pg_tz *tz, long int *gmtoff)
Definition: localtime.c:1746
#define gmtptr
Definition: pgtz.h:35
static int leaps_thru_end_of(const int y)
Definition: localtime.c:1305
static int charcnt
Definition: zic.c:163
char TZname[TZ_STRLEN_MAX+1]
Definition: pgtz.h:62
bool pg_interpret_timezone_abbrev(const char *abbrev, const pg_time_t *timep, long int *gmtoff, int *isdst, const pg_tz *tz)
Definition: localtime.c:1652
bool tt_ttisstd
Definition: pgtz.h:31
#define SECSPERMIN
Definition: tzfile.h:103
const char * name
Definition: encode.c:521
#define YEARSPERREPEAT
Definition: private.h:112
static bool increment_overflow_time(pg_time_t *, int32)
Definition: localtime.c:1468
#define MAXVAL(t, b)
Definition: private.h:85
static const char * getnum(const char *strp, int *nump, int min, int max)
Definition: localtime.c:626
static const int year_lengths[2]
Definition: localtime.c:581
union input_buffer u
Definition: localtime.c:196
static bool increment_overflow(int *, int)
Definition: localtime.c:1450
int tm_year
Definition: pgtime.h:32
static zic_t trans[TZ_MAX_LEAPS]
Definition: zic.c:382
#define TZ_MAX_TYPES
Definition: tzfile.h:96
int tt_abbrind
Definition: pgtz.h:30
char tzh_ttisstdcnt[4]
Definition: tzfile.h:39
#define TYPE_BIT(type)
Definition: private.h:71
int i
int pg_open_tzfile(const char *name, char *canonname)
Definition: findtimezone.c:64
static struct pg_tm * localsub(struct state const *sp, pg_time_t const *timep, struct pg_tm *tmp)
Definition: localtime.c:1174
#define EPOCH_YEAR
Definition: tzfile.h:136
int tm_yday
Definition: pgtime.h:34
#define UNIX_EPOCH_JDATE
Definition: timestamp.h:162
#define POSTGRES_EPOCH_JDATE
Definition: timestamp.h:163
struct pg_tm * pg_gmtime(const pg_time_t *timep)
Definition: localtime.c:1295
bool tt_ttisgmt
Definition: pgtz.h:32
bool goahead
Definition: pgtz.h:48
#define SECSPERREPEAT
Definition: private.h:124
static const char * getqzname(const char *strp, int delim)
Definition: localtime.c:610
#define TYPE_SIGNED(type)
Definition: private.h:75
#define close(a)
Definition: win32.h:17
int typecnt
Definition: pgtz.h:45
int tm_sec
Definition: pgtime.h:27
#define EOVERFLOW
Definition: private.h:38
#define SECSPERHOUR
Definition: tzfile.h:109
static struct pg_tm * timesub(pg_time_t const *, int32, struct state const *, struct pg_tm *)
Definition: localtime.c:1312
static const char gmt[]
Definition: localtime.c:50
int tm_min
Definition: pgtime.h:28
#define read(a, b, c)
Definition: win32.h:18
static bool differ_by_repeat(const pg_time_t t1, const pg_time_t t0)
Definition: localtime.c:169
#define TWOS_COMPLEMENT(t)
Definition: private.h:78
static struct pg_tm * gmtsub(pg_time_t const *, int32, struct pg_tm *)
Definition: localtime.c:1266
int defaulttype
Definition: pgtz.h:55
static const char * getzname(const char *strp)
Definition: localtime.c:591
char tzh_ttisgmtcnt[4]
Definition: tzfile.h:38